Cultured glial cells express the SNAP-25 analogue SNAP-23

Astrocytes release glutamate and aspartate in response to elevated intracel lular calcium levels, and it has been proposed that this occurs by a vesicu lar release mechanism, in which SNARE proteins are implicated. Although syn taxin, synaptobrevin, and cellubrevin have been shown to be expressed by cu ltured astrocytes, SNAP-25 has not been detected. By using immunocytochemic al, immunoblotting, and polymerase chain reaction techniques, the present s tudy demonstrates that SNAP-23, an analogue of SNAP-25, is expressed by ast rocytes both in culture and in rat cerebellum. These findings provide addit ional evidence that astrocytes release excitatory amino acids by a vesicula r mechanism involving SNARE proteins. SNAP-23 and also syntaxin 1 and cellu brevin were found to be expressed in glial precursor cells, oligodendrocyte s, and microglia. These data suggest that the t-SNAREs SNAP-23 and syntaxin 1 and the V-SNARE cellubrevin participate in general membrane insertion me chanisms involved in diverse glial cell functions such as secretion, phagoc ytosis, and myelinogenesis. (C) 1999 Wiiey-Liss, Inc.